Nodejs. Getting mixed data values from Postgres

I am hosting a node.js server using pm2 with 8 instances. The backend stack is using Sails.js, Redis and Postgres. The frontend is using Angular 1. The issue is that when a user requests to load their profile, it returns mixed data.
E.g, Their name, a different users picture, etc.

What could be the possible reasons why this is happening?
I believe they are doing session management with Redis. Would there by any issues with Sails.js/PM2/Redis/Postgres?